A6 Avant HVAC Blows Cold Air when Engine on low revs or Idle

[niall campbell]

in Dec ?

You may find over the next few days its going to get very cold

I would change the belt just now as 90,000 miles a nice round figure, see if you can get a metal pump rather than plastic if fitted and you can get one ?

Around £350 is the going rate for belt and pump change, peace of mind

[Jimbob21]

Hi just an update !! Have had timing belt changed and water pump at same time, pump was fine was the original fitted one with plastic impeller. not sure whether problem has been solved as am now back abroard and weather warmer but Air con Compressor clutch has now disintegrated so no air con ! Waiting to return to UK to get replacement pump. Will see then if problem has solved itself

[niall campbell]

hope so


as an interest did you get a pump with a metal impeller ?

[Jimbob21]

Update!!

Yes got new water pump with metal impeller, everything new seems to be fine. New Air Con Compressor fitted and working well. Still not convinced that it has cured the original fault of not blowing warm air as when i i change heat setting to high cabin does seem to warm up but center and side vents still blow cold air.

Audi A6 Avant 2.0l tdi Sport 2005 140

[niall campbell]

there are a lot of flaps, all with their own motors built into them


You need a full system scan with either Autel VAG505 or VCDS to see if it will pick up a fault

Will the car heat up if you switch from AUTO to ECON ?


I run my car the whole year with AUTO on, it wont affect your mpg on a diesel


I have had maybe 3 times, the centre being very hot compared to the side vents; but its always corrected itself

[Jimbob21]

Yes car seems to heat up when in eco mode but centre vents still blow cold, tried to change centre vent settings in setup but still blows coldish, having said that it is alot warmer than when i was in UK in Jan. Will now use Auto all the time and see if that improves it.

[_Tazman_]

Do the audis have duo valves like the mercs for water heating control?

As others have said a proper vcds or alt scan will cut out a lot of trial and error.

Hope you get it sorted.